Emulsion hydraulic fluid, concentrate and method of preparing same



United States Patent 3,222,284 EMULSION HYDRAULIC FLUID, CONCENTRATE ANDMETHOD OF PREPARING SAME George R. Cook, Arlington Heights, 111.,assignor, by

mesne assignments, to Union Oil Company of California, Los Angeles,Calif., a corporation of California No Drawing. Filed Oct. 6, 1961, Ser.No. 143,314 19 Claims. (Cl. 252-75) This invention relates to newcompositions of matter, and more particularly to hydraulic fluidcompositions. A specific feature of the invention is the discovery thatcertain critical relationships exist in the concentrations, types ofingredients, etc., in water-in-oil, emulsion-type hydraulic fluids.Another feature of the invention is the discovery that the ease ofemulsibility, the blend stability in concentrated and diluted form, theattainment of suitable viscosities, and the viscosity stability of thediluted emulsion under shear of fire-resistant hydraulic fluids of thewater-in-oil emulsion type are directly and critically influenced by thekind, amounts, and ratios of ingredients.

Fire-resistant hydraulic fluids may be pure synthetic materials, suchasphosphate esters, mixtures of phosphate esters, or various chlorinatedmaterials, or may be mixtures of water and water-soluble synthetics orwater-in oil emulsions, comprising a second and more recent type ofsnuifer fluids. This latter type, to which this invention relates,offers excellent fire resistance due to the release of a blanket ofsteam in the presence of high temperature. These emulsion-type fluidsoffer excellent fireresistance, acceptable lubricity, corrosionresistance, hydraulic efficiency, adequate film strength, high viscosityindex, oxidation stability, good cooling qualities, and compatibilitywith equipment. As a result, emulsion-type fluids are being used moreextensively in systems operating at high temperatures and pressuresWhere fire-resistance is important, such as in the hydraulic machineryin ships at sea, submarines, wind tunnels, mining equipment, missilelaunching, and in machinery handling hot ingots or molten metals, oroperating near sparks, flames, or hot metal surfaces. Some hydraulicsystems operate at temperatures as high as 650 F. and pressures as highas 3000 p.s.i. Standardized tests have been developed forfire-resistance, namely, the high-temperature test (pressure-ignitionspray test), the hot manifold test, and the pipe-cleaner test underSpecification MIIr-FJIOO. In addition to these criteria, hydraulicfluids must be devoid of toxic effects, must not harm metals or seals,should not foam or cause erosion, and must be compatible with machinerypaint.

The development of water-in-oil, emulsion-type hydraulic fluids meetingthese severe demands is diflicult because these fluids must also bestable in concentrate form, be easily emulsified, and form stableemulsions having suitable viscosities and viscosity stabilities asevaluated by the Vickers pump test. This test was developed by theindustry in cooperation with the Bureau of Mines to evaluate theemulsion stability under shear, simulating the conditions imposed inmodern hydraulic machinery, particularly for use in mining operations.The operating conditions are 1000 to 2000 p.s.i. at flow rates of atleast 2.0 to as high as 8.0 gallons per minute for 1000 hours. Thesetests may be conducted at pressures as high as 10,000 p.s.i.

To pass the Vickers pump test, the hydraulic fluid must not 3,222,284Patented Dec. 7, 1965 ice break down or permit excess wear of pump partsover the 1000-hour test period. Although no limits on the weight loss tobe tolerated have been established, a total weight loss of 0.0300 gm. isconsidered excellent. Also, the fluid is evaluated for adequate coolingof the system and for uniformity of viscosity throughout the time of thetest. Another feature of this invention is the development of anemulsion-type hydraulic fluid which not only meets'the generalrequirements aforesaid, but also passes the Vickers pump test.

Accordingly, a primary object of this invention is to providefire-resistant hydraulic. fluids. of the water-inroil emulsion type. V

An object of this invention is to provide fire-resistant hydraulicfluids of the water-in-oil emulsion type which meet the generalrequirements for hydraulic fluids in addition to qualifying for use athigh pressures and(or high temperatures. a

Another object of this invention is to provide fire-resistant hydraulicfluids of the water-in-oilemulsion type.

which exhibit emulsion stability in dilute and concentrated bility indiluted form under extreme pressure conditions,

as evaluated by the Vickers pump test, in addition to meeting the otherrequisites for such a fluid.

These and other objects of this invention will be described or becomeapparent as the specification proceeds.

Many unique problems have been found to be associated with theformulation of water-in-oil emulsions, and concentrates for theirpreparation, for use as fire-resistant hydraulic fluids. For example, inevaluating and screening a large number of fluids, it was found that thewater" content (which is all-important in the stability of solubleoilemulsions of the O/W type) plays no part in the problems of W/O emulsionstability. The use of various mutual solvents or couplers such asdiethylene glycol, hexylene glycol, butyl Cellosolve, etc.,' which areknown to be effective stability enhancers in O/ W emulsions, offered nosolution to the problem in W/O emulsions. Furthermore, various knownemulsifiers such as polyoxyethylene derivatives of fatty acids, estersof fatty acids, alkyl aryl sulfonates, and various surfactants, gavesatisfactory emulsions with 40% of water, but the emulsions failed theVickers pump test due to their breakdown. Additives re ported to beuseful for enhancement of lubricity or antiwear were evaluated and foundto be ineffective or detrimental. By experiments With W/O emulsions, itwas determined that the viscosity of the oil in the emulsion had little,if any, effect upon the apparent viscosity of the emulsion. Brightstocks, however, are excluded as the base oil because of theirinherently high viscosity. Distillate oils, such as neutral oils, formthe best base oil. With a corresponding water content, the substitutionof a 2000-vis. neutral for a IOO-Vis. neutral gave emulsions ofpractically the same viscosities.

I have found that by combining certain types of petroleum sulfonates inparticular proportions with certain metal alkyl dithiophosphates inparticular proportions, and combining this mixture at certain over-allconcentrations with distillate mineral oils, e.g., with neutral oils,concentrates exhibiting the desired stability, and emulsions therefrommeeting the severe Vickers pump test and other requirements heretoforementioned, can be obtained. The invention is more particularly describedin relation to a number of examples which are to be considered exemplaryand not limiting on the scope thereof.

Table I sets forth the composition of this invention in weight percentbased on the additives, active ingredients and on a W/O emulsion blendthereof.

Table i A. COMPOSITE OF CONCENTRATE BASED ON ADDITIV'ES Weight PercentLow Optimum High range Additive:

Commercial alkali metal petrol sulfonate 2. 50 3. 45-5. 19 6. Commercialalkaline earth metal alkaryl sulfonate 1. 00 1. 40-3. 36 4. 51Commercial metal dialkyl dithiophosphate 0.49 0. 92-1. 00 1. 50 Minerallubricating oil (balance) B. COMPOSITION OF CONCENTRATE BASED ON AC"TIVE INGREDIENTS Ingredient:

Alkali metal petroleum sulfonate... 1. 55 2 14-3. 22 3. 72 Alkalineearth metal alkaryl sulfonate 0. 45 0 63-1. 51 2.03 Metal dialkyldithiophosphate 0.47 0 88-0. 95 1. 43 Mineral lubricating oil (balanee)C. COMPOSITION OF W/O EMULSION (60% CONC.-|40% H2O) OF B In Table I, theconcentration of the mineral oil has been omitted to avoid theimplication that in each part of the table the concentrations appearingone over the other in a column are used to formulate a composition ofthis invention. Table I is intended to give the range of concentrationof each ingredient that can be used in the overall concentrate, forexample, the ratio of concentrations in weight percent alkali metalsulfonate to alkaline earth metal sulfonate is broadly between about1.55/ 2.03 or .71 to 3.72/.45 or 8.26, and preferably about 3.22/0.63 or5.27 to 2.14/1.51 or 1.4, and further provided that the total amount ofsaid sulfonates is greater than about 2.77 (2.14+0.63) and less thanabout 4.73 (3.22|1.51) weight percent. Preferably, the range of thetotal amount of said sulfonates is about 3.50 to 3.80 with the preferredamount being about 3.65 weight percent.

In making up concentrates using commercially available alkali metalsulfonates and alkaline earth metal sulfonates, as further hereindefined, appropriate adjustments in the amount of commercial addend,which generally is obtained as a mineral oil solution, are made to takeinto account the mineral oil or other diluent that is present. Theamounts of such oil or other diluents are taken into account in themineral oil portion of the compositions. The concentrations ofingredients in all parts of Table I are subject to modificationdepending on the active ingredients, based upon precise chemicalanalysis, of the addends used and also upon the amount of water used tomake the final W/O emulsion. The amount of metal shown provided theabove-defined limitations regarding the ratio of sulfonates and totalamounts of sulfonates are met. A broader range (based on activeingredients) of about 0.25 to 1.5 weight percent is specified forgeneral service. The dithiophosphate additive may contain small amounts,in the order of 1.0% by wt. of sulfonates, to aid in solubilizing samein mineral oil. Since this changesthe total sulfonate content by onlyabout 0.001% by weight at the most, it can be ignored.

The amount of water used to prepare the final W/O emulsion product issubject to some variation. The purpose of the water is to givefire-resistance properties to the product. According to the U.S. Bureauof Mines, between about 38% to 42% by weight of water gives the mostconsistent and safe fire-resistant qualities, with the optimum beingabout 40% by weight. These recommended amounts are varied throughout theindustry depending on Whether the proportions are established on avolume percent or weight percent basis. Generally, a loss of about 5% byweight of water causes a reduction in the fire-resistant qualities ofthe product. However, for many purposes adequate fire-resistance can beattained through the use of 25% by weight of water, with the balancebeing the mineral oil concentrate. There is some tendency for theemulsion to burn in a severe electric are when only 20% by weight ofwater is present, and at water concentrations above about 45% by weight,there is an increase in the apparent viscosity of the emulsion, causingcavitation in the pumps which results in failure to pass the Vickerspump test. Water concentrations below about 33% by weight do not giveadequate fire-resistance for most purposes. Consequently, the watercontent of the emulsions contemplated by this invention can have valuesranging from about 33 to 45% by weight, with the preferred concentrationbeing 33 to 41% by Weight.

A preferred embodiment of this invention consists of a fire-resistanthydraulic fluid concentrate having the foregoing proportions comprisingsodium petroleum sulfonate, calcium dodecyl benzene sulfonate, zincdialkyl dithiophosphate, wherein the alkyl group contains 6 to 8 carbonatoms, and a neutral mineral lubricating oil of the MCSR variety.

In order to illustrate the invention, a series of experiments aredescribed wherein a number of experimental emulsions were prepared usingditferent ingredients or addends, difiierent mineral oils, and waterscoming from different sources. Initial experiments established thatoilin-water emulsions preparedusing the best known commercialsulfonate-type detergents, emulsifiers, and coupling agents withpreferred types of oil and distilled water could not pass the Vickershydraulic pump test because of excessive wear of the pump parts,breakdown of the emulsion, or failure to allow the establishment of therequired pumping rates. Some of these oil-in-water emulsions, thoughstable and meeting the initial viscosity requirements, exhibited adeterioration of viscosity during the tests and almost a completebreakdown at the conclusion of the tests. Examples I to V areillustrative.

EXAMPLE I A series of oil-in-water emulsions containing from about 40%to 50% by volume of concentrates and consisting of petroleum sulfonates(9.92% to 12.48% by wt. based on the additives), 1.98% to 2.51%polyethylene glycol esters, assisting agents such as oleic acid, 0.29%to 0.33%, and Mid-Continent solvent refined mineral lubricating oils(19.8% to 36.0%), with distilled water in amounts ranging from about50.0% to 66.29%, were prepared, tested, and evaluated by means of theVickers pump test. All of these oil-in-water emulsions failed theVickers pump tests either because of poor pumping rates, the developmentof noise and excessive wear in the pump parts, loss of pump pressure, orfor other reasons. This EXAMPLE II A series of water-in-oil emulsionsand water dispersions was prepared containing as the emulsifiers suchmaterials as petroleum sulfonates, glyceryl mono-oleate, and suchassisting agents as hexylene glycol and highmolecular-weight alcohols,with and without metal dialkyl dithiophosphates, said materials beingpresent in amounts adjusted to give stable water-in-oil emulsions whenmixed with from 66% to 71% of MCSR oil and distilled water or with 63 to84% distilled water. None of these compositions passed the Vickers pumptest although the viscosities of the blends and their stabilities wereabove acceptable limits.

EXAMPLE III A water-in-oil emulsion containing 8.0% by wt. ofpolyethylene glycol 200 monolaurate, 4.0% polyethylene glycol 600mono-oleate, 66.0% MCSR lubricating oil, and 22.0% distilled water wasprepared. The emulsion had a viscosity at 100 F. of 876 SUS. At theconclusion of the Vickers pump test, which had a duration of threehours, the viscosity at 100 F. was 795 SUS and the pumping rate at thestart of the test was 2.0 g.p.m. at 1000 p.s.i. This pumping ratedropped to 1.8 g.p.m. at 480 p.s.i. at the conclusion of the test andthe required 1000 p.s.i. pressure could not be reached due to pumpvibration. This composition failed the Vickers pump test.

EXAMPLE IV A concentrate and water-in-oil emulsion having the followingcomposition in weight percent, on the basrs of the commercial additives,were prepared.

In preparing the concentrate, a base oil comprising 1.00% by wt. of thezinc dialkyl dithiophosphate, 66.73% 'SO/ I'OO F.N., and 32.27% 170/100RN. Was' used. This base oil was 93.33% of the concentrate and 56% ofthe emulsion. Storage tests indicated this formulation to be highlyacceptable as far as the stability of the concentrate and emulsion areconcerned, but the emulsion was not sufficiently shear stable towithstand the rigorous action of the Vickers pump test, and theemulsions were unstable after pumping for a short time. This formulationfailed the Vickers pump test.

EXAMPLE V A concentrate and water-in-oil emulsion having the followingcomposition in weight percent, on the basis of the additives used, wereprepared.

In preparing the concentrate, the base oil of Example IV was used andbecame 93.80% of the concentrate and Ingredients Emulsion Concentrate56.28% of the emulsion. The concentrate and emulsion wt. percent Percentwere extremely stable but the emulsion failed the Vickers pump test.Polyox ethylene sorbitan trioleate 1.08 1.80 sorbitgl partial fattyesters M2 L87 Attention was directed to water 1n oil emulsions, and Zincdialkyldithiophosphate-- g. g. 40 after a series of screening tests andVickers pump tests, 86 /28fitttfiittfititltttttir::::::: 18:07 301. thecomp s Table I were esaiplished as W 40-00 illustrative of the inventionas these compositions meet 100.00 100.00 the stability and performancetests, hereinafter more fully explained, for an =FRHF composition.

Table IA COMPOSITIONS OF FRHF CONCENTRATES AND EMULSIONS Blend No 12 1314 Concentrate 60%-40% by wt. Concentrate 60%-40% by wt. Concentrate60%-40% by wt,

emul. emul. emul.

Addenda Act. Addends Act. Addends Act. Addends Act. Addenda Act. AddendsAct.

Ing. Ing. Ing. Ing. lug. Ing.

mgredtileintsz P t l S If t e so um e to em H mm 4. 00 2. 48 2. 40 1. 495. 20 3. 22 3. 12 1.93 3. 2.14 2. 07 1.28

5 0. 93 0. 88 0. 56 0. 53 0. 93 0. 88 0. 56 0. 53 1. 00 0. 95 0. 60 5780/100 Neutral (Oil No. 1)- 62. 30 63. 80 37. 38 38. 28 170/100NNeutral((0)il lggvggfh 30. 17 31. 67 18.10 19. 00

100 Neut 1 20 LSWT 611100, 15 30. 17 31. 57 18.10 18. 94 100 Pale Oil(No. 3) 92.19 95. 40 55. 31 57. 24 13-1? Neutral (Oil N0. 5) I (92.19)(95. 40) (55. 31) (57. 24) Water 40.00 40. 00 40. 00 40. 00 40. 00 40,00

7 The B-P neutral oil, No. 5, was substituted for the 100 pale oil inthe concentrates and emulsions of Blend No. 14, which values are shownin parentheses. Taking into N0. 12 of Table IA, a further comparison wasmade with two commercially available hydraulic fluids purported to besuitable for use in mining equipment. The results are account the amountof ISW I oil in Blend No. 12, and shown in Table II.

Table II COMPARISON OF VICKE RS HYDRAULIC PUMP TEST DATA AT 1,000 P.S.I.

Product Blend N0. 12 FRIIF A FRIIF B Table I Type W/O Emulsion W/OEmulsion W/O Emulsion Total pumpage durng 1,000 hr. test (gals) 128,698113,181 120,223 Total Average Flow Rate (g.p.rn.) 2.15 1.89 2.00

Type of loss Mg. Percent Mg. Percent Mg. Percent Front Bushing 20. 7 0.0118 33. 8 0. 0189 26. 1 1 0. 0140 Rear Bushing. 20. 7 0. 0119 37.1 0.0207 25. 2 1 0. 0141 Rotor 22. 0. 0068 11. 0 0. 0034 53. 0 1 0. 0163Ring- 257. 0 0. 1165 406. 0 0.1834 256. 0 l 0. 1158 Vanes and Pin 162. 80. 4384 803. 4 I 2. 1138 100. 0 1 0. 2688 Total loss 483. 2 0.0518 1,291. 3 0. 1371 460. 3 1 0. 0491 1 These results were subject to questiondue to the disintegration of a cork float in the safety circuit. Thecork was trapped in the filter but could have changed the properties ofthe fluid to appear more favorable in the pump test.

Referring to Table II the FRHF A would be considered borderline andBlend No. 12 is shown to have successfully passed the Vickers pump test.

Since one of the crtical factors in formulating fire-resistant hydraulicfluids is the rubber-seal test, the example Blend No. 12 was evaluatedin accordance with ASTM D471 Method at 158 F. The results are shown inTable IH.

Table III RUBBER-SEAL TEST CONDUCTED WITH FIRE-RESISTANT HYDRAULIC FLUIDCON Rubber Specimens:

CENTRATE AND EMULSION Chicago Rawhide (Sirvene) Manufacture, Buna N-TypeA 2. Vickers Model 104-E-10 Pump Shaft Seal, part No. 188323 (presumablyBuna N) FRHF type Concentrate (Blend No. 12) Emulsion glend No. 12 inRubber Specimen Number 1 2 1 2 Run 1 Run 2 Run 1 Run 2 Run 1 Run 2 Run 1Run 2 Durometer (Hardness Value):

Initial value 92 92 After hours 92 89 After 168 hours 90 86 After 28days 92 83 Thickness (inches):

Initial value 061 After 70 hours 061 After 168 hours 0615 After 28 days061 Volume Change (percent):

After 70 hours 0 1 nil 0.5 7.5 9.9 8 6 12.9 1 6 After 168 hours 0 5 nil4.3 7. 5 9. 2 8 9 13.5 4 7 After 28 days 0 4 1111 3.3 14.6 8.1 16 4 14.14 7 TEST NOTES:

1. None of the seals showed any tendency to crack when bent back uponitself. 2. Those seals used with the FRHF emulsion were more pliable atend of test period than those tested in the concentrate.

3. No thickness or hardness measurements could be taken on Pump ShaftSeals.

the other containing 33.66% by weight of 80/ neutral, 14.46% by weightof 170/100 neutral, and 7.36% by wt. ISWT oil, are shown in Table IA andare additional examples of emulsions within the scope of this invention.

In order to obtain a more critical evaluation of Blend In order tofurther establish the unique physical properties of the fire-resistanthydraulic fluids of this invention, Blend No. 12 was furtherindependently evaluated with the Vickers pump test at a higher pressure,namely 1500 75 p.s.i.g. The results are shown in Table IV.

Table IV HYDRAULIC PUMP TEST AT 1500 P.S.I.G.

Pump Type: Vickers Vane Type, Model 105-010, Designed flow rate7.5 to8.0 g.p.m. (450 to 480 g.p.h.) Sample: 60% (wt) Blend No. 12 and 40%(wt.) water (a water-in-oil emulsion was formed) Test Hours, Cumulative116. 250 374 510 605 700 800 901. 5 1,013 Test Hours, Periodic 0 116. 5133. 5 124 136 95 101. 5 111.5 Gallonage Pumped, Cumulative- 53,907 115,945 171,697 233,265 273,622 313,800 356,403 400,327 448, 401 GallonagePumped, Per1odic 53, 907 62, 038 55, 752 61, 568 40, 357 40,178 42, 60343, 924 48,074 Flow Rate (g.p.h.), Gnmulative 462. 7 463.8 459. 1 457.4450.8 448.3 445.5 444.6 442. 6 Flow Rate (g.p.h.), Periodic 462. 7 464.6 448. 8 452. 7 424. 8 422. 9 426. 0 432. 8 431. 2 Operat ng Pressure(p.s.i.g.) 0 1, 500 1, 500 1,500 1, 500 1, 500 1, 500 1, 500 1, 500 1,500 Operatmg Temperature F.) 15 150 15 150 185 185 185 185 185 Test DataObtained:

Viscosity at 100 F. (SUS) 349 364 367 355 351 367 409 390 416 398Viscosity at 150 F. (SUS) 144 148 146 145 141 148 162 158 168 Viscosityat F. (SUS) 89 98 87 96 89 Percent Water (by volume) 36. 35 35. 0 35. 535. 0 35.0 34.0 35. 0 36. 0 37. 4 39 Miscellaneous: The followingadditions of fluid were made- At 650 hours, 2 qts. concentrate and 4qts. water. At 810 hours, 4 qts. concentrate and 4 qts. water. At 965hours, 4 qts. concentrate and 4 qts. water.

Weight (grams) Weight Loss (grams) Parts Percent of Loss From start toFrom Start to Start At 510 Hours At 1,013 Hours From start to From 510hrs. finish at 1,013 Finish 510 hrs. to 1,013 hrs. hrs.

183. 0372 183. 0002 182. 9528 0. 0370 0. 0474 0. 0844 0. 0461 177. 2394177. 2094 177. 1881 0. 0300 0. 0213 0. 0513 0. 0289 182. 4314 180. 5610180. 3330 1. 8704 0. 2280 2. 0984 1. 1502 323. 1153 322. 6431 322, 40300. 4722 0. 2401 0. 7123 0. 2205 Vanes and Pin 37.8296 37. 4766 37.15470.3530 0.3219 0. 6749 1. 7841 903. 6529 900. 8903 r 900. 0316 2. 7626 0.8587 3. 6213 Percent weight loss 0. 305 0. 095 0. 401

Blends. 13 and 14 and the two additional blends containing ISWT oil,when similarly tested, pass the Vickers pump test at pressures up to1500 p.s.i.g., the flammability tests, and the rubber-seal test, andexhibit acceptable stability in concentrate and emulsion form inaddition to passing the other requirements for fire-resistant hydraulicfluids.

FLAMMABILITY Table V The results shown in Table IV indicate that thecompositions of this invention have exceptional properties as evaluatedby the Vickers pump test.

Table V gives the results of flammability tests on Blend No. 12.

TESTS CONDUCTED WITH 60% BLEND NO. 12 AND 40% WATER FORMING A WATER-IN-OIL EMULSION [1. Federal Test Method Standard 352-T, Efiect ofEvaporation on Flammability ipe Cleaner Test)] Sample: Emulsion takenfrom Hydraulic Pump Test reservoir at start of test.

Sample: Emulsion taken from Hydraulic Pump Test reservoir after 1,013hrs. of testing.

Average Minimum Acceptable--.

5:6 (Pass) 24 51 (Pass) is 23.8 (Pass) 12 [2. 13.8. BUREAU OF MINESFLAMMABILI'IY TEST] Sample: Emulsion taken from Hydraulic Pump Testreservoir at start of test. Spontaneous Ignition Temperature ofEmulsion, 745 F. (600 F. Minimum Required.)

Conditions: A spray test at 150 p.s.i. and fluid temperature of 150 F.

N.b. These tests were also conducted with samples drawn from thehydraulic pump test at approximately IOU-hour intervals. The resultsobtained were essentially the same as those reported herein.

A number of other fire-resistant hydraulic fluid emulsions preparedusing the concentrations of ingredients set forth herein also pass theflammability tests shown in In order to establish the essential,critical nature of the proportions of alkali metal petroleum sulfonateand alkaline earth metal sulfonates, a number of compositions Table V.

In evaluating a number of concentrates and emulsions within and outsideof the essentially critical limits of addend concentration, I found thatthe concentrates were generally stable and emulsions prepared therefrom,except using the preferred materials was formulated and tested foremulsion stability under different conditions, that is, one week at 80F. and two weeks at 140 F. The results are shown in the following TableVI.

Table VI EMULSION STABILITY TESTS USING MCSR OIL Composition WeightPercent Active Ingredients I Blend Number 12 15 16 17 18 19 20 21 22 2324 25 Sod. etrol. Sillf 1 49 1. 40 1. 58 1. 58 1. 49 1. 77 2.00 2. 08 1.95 2. 00 2.12 2. 32 Ca DB Sulf 0.70 77 63 74 81 .77 27 .22 32 .32 .32 ZnDialkyl dithiophosphate-. 0. 53 53 53 53 53 53 53 53 53 53 53 53 Blendof Neutral Oils 57. 28 57. 30 57.26 57.15 57.17 56. 93 57. 20 57.1757.20 57.15 57.00 56. Water 40. 00 40. 00 40. 00 40. 00 40. 00 40. 0040. 00 40. 00 00 40. 00 40. 00 40. 00 Emulsion Stability, One week at 80F- Ex. Ex. Fail B. Fail Emulsion Stability, Two weeks at 140 F.-. B.Fail B. B. 13. Fail Composition, Weight Percent Active Ingredients BlendNumber- 26 27 28 29 13 30 31 32 33 34 35 36 Sod. Petrol Suli 2. 24 2.25 1. 88 1. 91 1. 93 1. 82 1. 71 1. 1. 57 1. 49 1. 34 1.38 Ca DB Sulf.37 .36 .32 .37 .38 .46 .54 .62 .75 .70 .65 .78 Zn Dlalkyldithiophosphate 53 53 53 53 53 53 53 53 53 53 Blend of Neutral Oils56.86 56. 86 57. 27 57.19 57.16 57. 19 57.22 57.25 57. 15 57.28 57.4857.31 Water 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00 40.00 40. 00 40. 00 40. 00 Emulsion Stability, One week at 80 I- EmulsionStability, Two weeks at 140 F-. B. Fail Ex. Ex. Ex. Ex. B. B. Fail FailFail Fail Ex. Excellent. B. =Bordcrline. Fail=Failure.

those outside the essential limits, satisfactorily passed the Vickerspump test. However, some of the emulsions prepared therefrom were notsufliciently stable for extended periods of time to meet the industryrequirements of suflicient stability to be marketed in emulsion form orto Withstand periods of storage or shutdown of the hydraulic machineryusing the emulsions. I have found that both the type of minerallubricating oil and the Water used in preparing these emulsions has adecided influence on the emulsion stability. It must be kept in mindthat many of the emulsions hereinafter evaluated as unacceptable arenevertheless useful since they still meet the critical Vickers pump testand the many other critical requirements for a fire-resistant hydraulicfluid.

contain 10% and 20% ISWT oil.

All of the compositions shown in Table VI are on an active ingredientbasis. The blands of neutral oils used in FRHF Blends Nos. 12, 15 and 19are the same as pre- 65 viously used, that is, 66.73% of /100 finishedneutral,

7 5 comes borderline or unacceptable.

In order to further demonstrate the effects of variations of theconcentrations of the active ingredients on the I emulsion stability, aseries of extensive emulsion stability tests were conducted up to 60days time, using both Accordingly, the compositions of this inventionare defined as fire-resistant hydraulic fluids, characterized by meetingthe tests herein enumerated, containing, in concentrate form, a majorportion of a mineral lubricating distilled water and demineralizedwater. The results for oil, preferably of the MCSR variety, betweenabout 1.55 the former are shown in Table VII. to 3.72 weight percent ofan alkali metal petroleum sul- Table VII EMULSION STABILITY TESTSComposition By Weight Percent Active Ingredients Blend Number 37 38 3940 41 42 43 44 45 46 47 Sod. Petrol. Sulf 1.81 1. 49 1. 43 1. 35 1.32 1. 28 1. 25 1. 21 1. 17 1.12 1. 36 Ca. 13.13. Sulf .39 .70 -.76....81.. -87 .91 .94 .98 1. 02 1.17 .93 Zn Dialkyl dithiophosphate .57.57 .57 .57 .57 .57 .57 .57 .57 .57 .57 MCSR on 57. 23 57.24 57. 2457.27 57.24 57.24 57.24 57. 24 57.24 57.14 57.14 40. 00 40. c0 40. 0040. 00 40.00 40. 00 40. 00 40. 00 40. 00 40. 00 40. 00

Ex. Ex. Bx. Ex. Ex. Ex. Ex. Ex. Ex.

Ace. Ace. Ace. Ex. Ex. Ex. Ex. Ex. Ex.

1 B. Ace 400. Ex. Ex. Ex. 'Ace. Ace. Aec.

. Ex. 1 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex.

Ace. Ace. Ace. Ace. Ex. Ex. Ex. Ex.. Ex.

B. B. B. Ace. Ace. Ace. B. Fail B.

Ace. Ace. Ex. Ex. Ex. Ex. i Ex. Ex. Ex.

B. B. Aceo Ace. Ex. Ex. Ace. B. B.

B. B. Ace. Ace. B. B. Fail Fail Fail *Distilled mo: Ex.= ei cellent.Acc.=aeceptable. B=horderline. Fail=failure.

likely to be stored longer than 60 days at temperatures a-bove 100 F. orbelow 32 F., in the main, compositrons 3710 46.. meet the generalemulsion stability requirements, and such compositions representadditional eka'mplescoming within this invention. The import 'of' thedata in Table VII is mainly to point up the effect of slight changes insulfonate ratios as regards the attainment of long-term storagestability. In every instance, even with the emulsions which fail onagitation or use, the emulsion is restored and is suitable,for use.Blend No. 47 was prepared at the same sodium sulfonate to calciumsulfonate ratio (on an active ingredient basis) as Blend N0. 12, butwith a greater quantity of each sulfonate. The stability data on thesetwo blends is identical, but the viscosity of Blend 47 is higher thanpractical for the invented purpose. An identical series of blends tothose reported in Table VII was prepared, using demineralized water, andthe stability data for the emulsions therefrom was identical to thatshown in Table VII. The use of tap water produces compositionsexhibiting reduced levels of emulsion stability, although, as in thecase of the demineralized water, the emulsions pass all of the othertests for a fire-resistant hydraulic fluid. Accordingly, Blends Nos.12-46 all represent examples of compositions coming within the scope ofthis. invention.

The ingredients used in the compositions of this invention are availablecommercially and well known in the art.

fonate, about 0.45 to 2.03 weight percent of an alkaline earth metalalkaryl sulfonite, and about 0.47 to 1.43 weight percent of a metaldialkyl dithiophosphate. The foregoing concentrates are blended withabout 33% to 42% of water. Other ingredients may be incorporated in thecompositions of this invention without departing from the spiritthereof. The principal ingredients are hereinafter more fully definedand illustrated.

The alkali metal petroleum sulfonates are oil-soluble alkali metal saltsof mahogany sulfonates formed from the treatment of petroleumdistillates, preferably from Pennsylvania grade oil or naphthenic-basecrude, with fuming sulfuric acid, sulfur trioxide, or sulfur trioxidecomplexes, followed by separation of the green sulfonie acid sludge andneutralization of the acid-treated oil with the appropriate alkali metalbase or oxide. The mahogany sulfona-tes can be extracted from theunreacted oil by treatment with an organic solvent, such as an aqueousalcoholic solution. Upon distillation of the alcoholic solution,'asdescribed in U.S. Patent 2,125,305, the alkali metal mahogany sulfonateis recovered. These detergent materials are commonly described as alkalimetal petroleum sulfonates, or alkali metal mahogany sulfonates derivedfrom a naphthenicor paraffin-base crude. They have average molecularweights of about 500 to 550, preferably of about 500 to 530.

Examples are sodium mahogany sulfonate, potassium mahogany sulfonate,lithium mahogany sulfonate, cesium mahogany sulfonate, rubidium mahoganysulfonate, and mixtures thereof, having an average molecular weight ofabout 500 to 550 and derived from naphthenic or Pennsylvania paraffiniccrudes. Sodium and potassium petroleum sulfonates are preferred.

The analysis of a typical alkali metal petroleum sulfonate, such as wasused in Blend No. 12 and identified as sodium petroleum sulfonate(Sherosope T), a proprietary product of the Bryton Chemical Company, isshown in Table VIII.

Table VIII Controlling Min. Max.

Method 1 Typical Analysis Sodium Sulionates (wt percent) 59. 8 MineralOil (wt. percent) 34. 4 Inorganic Salts (wt. percent) 0. 4 Water (wt.percent) 3. 5 Free NaOH (wt. percent) 0. 01 Sodium Carboxylate (wt.percent) 2. 5 Average Molecular Wt 513 Specific Gravity, (SO/60 F. 1.0313 API Gravity 5. 7 Sulfated Ash (wt percent) 9. 2 Acid umber 0. 03Base Number 0.93 Viscosity at 210 F. (S.U.S.) 2, 934 Pour Point F.) +70Weight per gallon (lbs.) 8. 590

Inorganic Salts Sodium Carbonate...

1 Determined by ASTM method as indicated. 2 Wide range. The oil-solublealkaline earth metal alkaryl sulfonates, which are balanced with thealkali metal petroleum sulfonate in accordance with this invention, havethe general formula,

[( )n SOs-12M where (R) is one or more alkyl, alkaryl or aralkyl groups,n having a value of 1 to 5 or more, and the aromatic nucleus may be asingle or condensed ring, or a partially hydrogenated ring. R willgenerally and preferably contain 10 to 14 carbon atoms, and where two Rgroups are present, the total number of carbon atoms in thesesubstituent groups is from 17 to 36 per sulfonic acid molecule. Theaverage molecular weight of the alkaline earth metal alkaryl sulfonatesused herein may be from about 40 925 to 975 and preferably is about 940to 970. In this connection, one particular alkaline earth metal alkarylsulfonate tested, having an average molecular weight of 890, wasunsuitable. The preferred alkaline earth metal Examples of otheralkaline earth alkaryl sulfonates are:

Strontium undecylnaphthalene sulfonate Calcium undecylbenzene sulfonateCalcium dodecylbenzene sulfonate Barium dodecylbenzene sulfonate 30Strontium dodecylbenzene sulfonate The analysis of a typical alkalineearth metal sulfonate, such as was used in Blend No. 12 and identifiedas calcium dodecylbenzene sulfonate (Bryton Calcium Sulfonate aproprietary product of the Bryton Chemical Company, is shown in TableIX.

Table IX REPRESENTATIVE CALCIUM DODECYL BENZENE SULFONAIE ASSAYControlling Method 1 Typical Properties Min. Max

Calcium sulionates (wt. percent)" 43. 8 (D 1216) 45.0 Mineral Oil (wt.percent) 53. 0

Water (wt. percent) r. 1.0

Inorganic Salts (wt. percent) 0.9

Basieity as 03(0H); (wt percent). 1. 6

Calcium Carboxylate (wt percent). 0. 1

Average Molecular Wt r. 944

Specific Gravity, ./60 F 0. 9554 API Gravity 16. 6

Sultated Ash (w 10. 2

Base Number 24. 6

Viscosity at 210 F (S U S 160.1

Pour Point F. +5

Weight per gallon (lbs.) 7. 957

1 Determined by ASTM method as indicated. 2 Close range.

alkaryl sulfonates are calcium and barium dodecylbenzene sulfonates andtheir mixtures.

Methods of preparing and purifying these alkaline earth metal sulfonatesare described in the prior art, e.g., United States Patents 2,760,970,Le Seur: 2,763,615, Faust; 2,839,470, Warren et al.; 2,856,361,Schlicht; 2,861,951, Carlyle; 2,880,173, Honeycutt; 2,883,340, Wasley etal.; 2,902,448, Collins; 2,943,052, Carlyle et al.; and 2,947,694,Cragson.

The heavy-metal salt of an alkyl dithiophosphate used in accordance withthis invention is preferably a zinc or cadmium salt of a dialkyldithiophosphate of the formula:

wherein R is an alkyl radical having from 4 to 10 carbon atoms, and M iszinc or cadmium. Although other tech- -'17 niques are available, ingeneral these substances are prepared by reacting the correspondingaliphatic alcohol with phosphorus pentasulfide to form the esters. Theresulting esters are acidic and readily form salts with bases of themetal M, i.e., with the oxides, hydroxides, sulfides, or carbonates. TheR-group may be straight-chain, branchedchain, or cycloaliphatic instructure. The metal salts falling within the definition are oil-solubleand are stable components in the concentrates or dilute emulsions. It ispreferred that R have 6 to 8 carbon atoms. Examples include Zinc dihexyldithiophosphate Zinc dioctyl dithiophosphate Zinc dinonyldithiophosphate Zinc dibutyl dithiophosphate 18 Zinc di-t-butyldithiophosphate Zinc di-pentyl dithiophosphate Cadmium dibutyldithiophosphate Cadmium dihexyl dithiophosphate Cadmium dicyclohexyldithiophosphate Cadmium didecyl dithiophosphate The following Table Xgives the chemical and physical characteristics of a typical zincdialkyl dithiophosphate (namely the proprietary compound identified asOronite OLOA 262), such as was used in the preferred blend, No. 12. Thisproduct has alkyl groups of 6 to 8 carbon atoms, identifiedas hexyl,heptyl, and octyl groups.

Table XI gives the chemical and physical characteristics of the minerallubricating oils used in the preferred compositions of this invention,and in other blends that have been prepared and tested.

*Determined by ASTM method as indicated.

Table XI CHEMICAL AND PHYSICAL CHARACTERISTICS OF MINERAL LUB RICAIIN GOILS Characteristics (ASTM Methods) Oil Identification No. H

API Sp. Gr., Flash, Fire, Via/100 F., Gravity, 60/60 1?. F. F. SUS

degs.

1. 80/100 MCSR Neutral 35. 9 0. 8453 79. 7 2. 170/100 MSOR NeutraL. 81.3 0. 8692 172.3 3. 100 Pale Oil 22. 4 0. 9189 102 4. 100 Neutral (L).22. 5 0. 9188 105 5. B-P-Neutral 22.3 0.9195 109 6. B-P-Neutia 22. 20.9201 113. 5 7. 100 Pale Oil 21. 7 0. 9236 103. 1 8. 100 Pale O 22. 20.9206 104. 8 9. 100 Pale O 22.4 0.9194 99,7 10. 100 Pale O 22.1 0.9212104.5 11. 100 Pale 011 22.7 0.9176 103.8 12. 100 Pale O11 21.8 0.9230102. 9 13. 100 Pale Oil 21. 8 0. 9230 102. 5 14. 80/100 MCSR Neut. and10% ISWT 35.6 0. 8458 81.2 15. 170/100 MCSR Neut. and ISWT 31. 4 0. 8686175. 7

Characteristics (ASTM Methods) Oil Identification No. Interfacial Vial,Vis.l Pour Acid No. Tension at 130 F. 210 F. V.I. Pt., F. (1948) 88 F.oil (SUS) (S US) against water (dynes cm.)

1. 80.100 MCSR Neutral 56.0 37. 5 99 -=10 0. 03 2. 170/100 MCSR Neutral.93. 2 44. 7 99 0 0.05 3. 100 PaleOil 62.9 38. 1 23 60 0.03 4. 100Neutral (L) 64. 2 38. 2 39 40 0. 03 5. B-P-Neutral. 38 18 -'45 6.B-P-Neutral 66.6 38.8 14 0.03 7. 100 Pale Oil 61. 3 38.1 18 0. 03 35. 58. 100 Pale 011.. 38. 3 22 55 0. 03 38. 4 9. 100 Pale Oi1 38.1 28 55 0.03 37. 7 10. 100 Pale Oil 38. 3 19 50 0. 03 38. 4 11. 100 Pale Oil 38. 219 50 0. 03 40. 3 12. 100 Pale Oil. 38. 2 21 55 0. 03 40. 1 13. 100 PaleOil 38.1 21 -55 0. 03 41.3 14. /100 MCSR Neut. and 10% ISW'I.. 56. 7 37.8 103 0 0. 03 35. 3 15. 170/100 MCSR Neut. and 20% ISWT .94. 9 45. 0 00. 03 43. 3

The aniline points of the lubricating oils shown in Table XI vary fromabout 140 to 150 F., and the oils may contain from about 1.5 to 2.5 Wt.percent sulfur. Oils Nos. 3, and 7-13 are products of the Macmillan OilCompany, oil No. 4 is a product of the Lion Oil Company, and oils Nos. 5and 6 are products of the Berry Asphalt Company.

To illustrate the method of preparation of the FRHF compositions of thisinvention, the following example is given:

About 165 lbs. of calcium petroleum sulfonate is preheated to about 100F. to facilitate handling, and 4,405 pounds of neutral oil are chargedto a clean mixing kettle, agitated and heated to about 150 F.Forty-eight pounds of zinc dialkyl dithiophosphate are added to theheated oil, agitation is continued, and the temperature maintained at140 to 150 F. The warm calcium petroleum sulfonate is added, andagitation continued with the temperature maintained at 135 to 145 F.;then 165 pounds of sodium petroleum sulfonate are added to the mixture,and agitation is continued for about one hour after the last addition,with the temperature held at 130 to 140 F. Stirring is continued forabout one hour, and the temperature is maintained above about 120 F. Atthis point, samples may be taken for analysis as to base No. (ASTMD-664), which should be within the range of about 0.7 to 1.7, acid No.(ASTM D-974), which should be about 1.00 to 1.4, and sulfated ash (ASTMD-874), which should be in the range of about 0.66 to 0.80. Also, anemulsion can be prepared by mixing 120 grams of concentrate at aboveabout 120 F. with 80 grams of distilled water, with water at roomtemperature. Acceptable emulsifying properties are evidenced at thispoint by emulsification with less than 10 minutes of mixing.

Following these analyses and the preparation of stable samples, all ofthe water, i.e., 3,186 lbs. deionized water or distilled water, is addedas rapidly as possible without agitation during the addition of water.At this time, the temperature of the mixture should not be less than 90F., and not greater than 130 F. The emulsion is then mixed for about 2hours and cooled as much as possible. The water content (ASTM D-95) inthis example is about 37.5 to 39.0% by volume, and the emulsion isstable after one hour at 150 to 160 F.

The following Table XII gives the physical properties of a concentratecontaining 3.45% (2.14% by wt. on active ingredient basis) of sodiumpetroleum sulfonate (Sherosope T or Petronate CR), 3.36% (1.51% byweight on active ingredient basis) of calcium dodecylbenzene sulfonate(Bryton Calcium Sulfonate 45), 1.00% zinc dialkyl dithiophosphate(Oronite 262 or Lubrizol 609), and 92.19% neutral oil, which may beMacmillan 100 pale oil, Lion 100 neutral, or Berry Permaseal neutral,and also the properties of the emulsion prepared therefrom.

Table XII CONCENTRATE (BLEND NO. 37)

Property Vis. at 100 F. (SUS) Vis. at 210 F. (SUS) H2O Content, wt.percent API gravity Sp. Gr. at 60l60 F. Flash Point Fire Point F.)Aniline Point F.) Pour Point F.) sulfated Ash (wt. percen Base No. (ASTMD-664) (Ks'ilii 13251311:

l a (dynes/em.)

FIRE-RESISTANT HYDRAULIC-FLUID W/O EMULSION By Weight By Volume 61.75%(Blend N0. 37). 38.25% Distilled or deionized water.

Apparent Viscosity at F. (before use). 423 SUS. Apparent Viscosity at F.(before use). 217 SUS. Sp. Gr. at 60/60 F 0.9507. API Gravity 16.4".Weight per gallon 7.967 lbs.

The embodiments of this invention in which an exclusive property orprivilege is claimed are defined as follows.

1. A hydraulic-fluid concentrate consisting essentially of a majorportion of a neutral mineral lubricating oil and the followingingredients:

Ingredient- Weight percent Alkali metal petroleum sulfonate (mol.

Wt. about 500-550) 1.55 to 3.72

wherein the ratio of concentration of alkali metal petroleum sulfonateto alkaline earth metal sulfonate is about 0.71 to 8.26, and the totalamount of said sulfonates is greater than about 2.77 weight percent andless than about 4.73 weight percent.

2. A hydraulic-fluid concentrate in accordance with claim 1 in whichsaid alkali metal petroleum sulfonate is sodium petroleum sulfonate.

3. A hydraulic-fluid concentrate in accordance with claim 1 in whichsaid alkaline earth metal alkylaryl sulfonate is calcium dodecylbenzenesulfonate.

4. A hydraulic-fluid concentrate in accordance with claim 1 in which thetotal amount of said sulfonates is about 3.50 to 3.80 weight percent.

5. A hydraulic-fluid concentrate in accordance with claim 4 in which thetotal amount of said sulfonates is about 3.65 weight percent.

6. A hydraulic-fluid concentrate consisting essentially of a majorportion of a neutral mineral lubricating oil and the followingingredients:

Ingredient- Weight percent Alkali Metal petroleum sulfonate (mol.

wt. about 500-550) 2.14 to 3.22

wherein the ratio of concentration of alkali metal petroleum sulfonateto alkaline earth metal sulfonate is about 0.71 to 8.26, and the totalamount of said sulfonates is greater than about 2.77 weight percent andless than about 4.73 weight percent.

7. A hydraulic-fluid concentrate in accordance with claim 6 in whichsaid alkali metal petroleum sulfonate is sodium petroleum sulfonate.

8. A hydraulic-fluid concentrate in accordance with claim 6 in whichsaid alkaline earth metal alkylaryl sulfonate is calcium dodecylbenzenesulfonate.

9. A hydraulic-fluid concentrate in accordance with claim 6 in which thetotal amount of said sulfonates is about 3.50 to 3.80 weight percent.

10. A hydraulic-fluid concentrate in accordance with claim 6 in whichthe total amount of said sulfonate is about 3.65 weight percent.

11. A hydraulic-fluid concentrate consisting essentially of a majorportion of a neutral mineral lubricating oil, about 2.48% by weight ofsodium petroleum sulfonate, about 1.17% by weight of calciumdodecylbenzene sulfonate, and about 0.88% by weight of zinc dialkyldithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

12. A hydraulic-fluid concentrate consisting essentially of a majorportion of a neutral mineral lubricating oil, about 1.93% by weight ofsodium petroleum sulfonate, about 0.38% by weight of calciumdodecylbenzene sulfonate, and about 0.53% by weight of zinc dialkyldithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

13. A hydraulic-fluid concentrate consisting essentially of a majorportion of a neutral mineral lubricating oil, about 2.14% by weight ofsodium petroleum sulfonate, about 1.51% by weight of calciumdodecylbenzene sulfonate, and about 0.95% by Weight of zinc dialkyldithiophosphate in which the alkyl groups contain 6 to 8 carbon atoms.

14. The method of preparing a hydraulic-fluid concentrate which consistsin mixing a neutral mineral lubricating oil with a metal di-C to C alkyldithiophosphate wherein the metal is of the group consisting of zinc andcadmium at a temperature of about 140 to 150 F., adding an alkali metalpetroleum sulfonate having a molecular weight of about 500 to 550 to themixture while same is maintained at said temperature, adding an alkalineearth metal alkylaryl sulfonate having an average molecular weight ofabout 925 to 975 and containing 10 to 14 carbon atoms in the alkylportion and said aryl portion being a member of the group consisting ofphenylene and naphthylene to said mixture at a temperature of about 130to 140 F., stirring said mixture for about one hour at a temperature ofabout 120 F., and allowing said mixture to cool.

15. A fire-resistant hydraulic fluid consisting essentially of anemulsion of about 33 to 45 by weight of a water phase and about 67 to55% by weight of an oil phase which consists in a major portion of aneutral mineral lubricating oil and the following ingredients:

Ingredient- Weight percent Alkali Metal petroleum sulfonate (mol.

wt. about 500-550) 1.55 to 3.72

wherein the ratio of concentration of alkali metal petroleum sulfonateto alkaline earth metal sulfonate is about 0.71 to 8.26, and the totalamount of said sulfonates is greater than about 2.77 weight percent andless than about 4.73 weight percent.

16. A fire-resistant hydraulic fluid consisting essentially of anemulsion of about 33 to 45% by weight of a water phase and about 67 to55 by weight of an oil phase which consists in a major portion of aneutral mineral lubricating oil and the following ingredients:

Ingredient- Weight percent Alkali metal petroleum sulfonate (mol wt.about 500-550) 2.14 to 3.22 Alkaline earth metal alkylaryl sulfonate(av. mol. wt. about 925-975) containing 10 to 14 carbon atoms in thealkyl portion and said aryl portion being a member of the groupconsisting of phenylene and naphthylene 0.63 to 1.51 Metal di-C C alkyldithiophosphate wherein the metal is of the group consisting of zinc andcadmium 0.88 to 0.95

wherein the ratio of concentration of alkali metal petroleum sulfonateto alkaline earth metal sulfonate is about 0.71 to 8.26, and the totalamount of said sulfonates is greater than about 2.77 weight percent andless than about 4.73 weight percent.

17. A fire-resistant hydraulic fluid consisting essentially of anemulsion of about 33 to 45 by weight of a Water phase and about 67 to55% by Weight of an oil phase which consists in a major portion of aneutral mineral lubricating oil, about 2.48% by weight of sodiumpetroleum sulfonate, about 1.17% by weight of calcium dodecylbenzenesulfonate, and about 0.88% by Weight of zinc dialkyl dithiophosphate inwhich the alkyl groups contain 6 to 8 carbon atoms.

18. A fire-resistant hydraulic fluid consisting essentially of anemulsion of about 33 to 45 by weight of a water phase and about 67 to55% by weight of an oil phase which consists in a major portion of aneutral mineral lubricating oil, about 1.93% by weight of sodiumpetroleum sulfonate, about 0.38% by weight of calcium dodecylbenzenesulfonate, and about 0.53% by weight of zinc dialkyl dithiophosphate inwhich the alkyl groups contain 6 to 8 carbon atoms.

19. A fire-resistant hydraulic fluid consisting essentially of anemulsion of about 33 to 45% by weight of a water phase and about 67 to55 by weight of an oil phase which consists in a major portion of aneutral mineral lubricating oil, about 2.14% by Weight of sodiumpetroleum sulfonate, about 1.51% by weight of calcium dodecylbenzenesulfonate, and about 0.95% by Weight of zinc dialkyl dithiophosphate inwhich the alkyl groups contain 6 to 8 carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 2,913,411 11/1959Schiermeier 25249.5 2,961,404 11/1960 Francis 252 JULIUS GREENWALD,Primary Examiner.

ALBERT T. MEYERS, Examiner.

1. A HYDRAULIC-FLUID CONCENTRATE CONSISTING ESSENTIALLY OF MAJOR PORTIONOF A NEUTRAL MINERAL LUBRICATING OIL AND THE FOLLOWING INGREDIENTS: 15.A FIRE-RESITANT HYDRAULIC FLUID CONSISTING ESSENTIALLY OF AN EMULSION OFABOUT 33 TO 45% BY WEIGHT OF A WATER PHASE AND ABOUT 67 TO 55% BY WEIGHTOF AN OIL PHASE WHICH CONSISTS IN A MAJOR PORTION OF A NEUTRAL MINERALLUBRICATING OIL AND THE FOLLOWING INGREDIENTS: